Re: [PATCH 06/16] drm/i915/dp_mst: Move the check for dotclock at the end

[Imre Deak <imre.deak@intel.com>]

On Wed, Jan 28, 2026 at 07:36:26PM +0530, Ankit Nautiyal wrote:
> Refactor the mode_valid to have all joiner dependent stuff together and
> place the check for dotclock limit at the very end.
> 
> This will help in the following refactor to iterate over the joiner
> candidates and find the best joiner candidate that satisfy all checks
> and limits.
> 
> v2: Update status to MODE_CLOCK_HIGH if max_dotclock check fails. (Imre)
> 
> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_dp_mst.c | 22 ++++++++++++++++-----
>  1 file changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_mst.c b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> index 24f8e60df9ac..24b0020acad0 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_mst.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_mst.c
> @@ -1470,20 +1470,19 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
>  	 *   corresponding link capabilities of the sink) in case the
>  	 *   stream is uncompressed for it by the last branch device.
>  	 */
> -	num_joined_pipes = intel_dp_num_joined_pipes(intel_dp, connector,
> -						     mode->hdisplay, target_clock);
> -	max_dotclk *= num_joined_pipes;
> -
>  	ret = drm_modeset_lock(&mgr->base.lock, ctx);
>  	if (ret)
>  		return ret;
>  
> -	if (mode_rate > max_rate || mode->clock > max_dotclk ||
> +	if (mode_rate > max_rate ||
>  	    drm_dp_calc_pbn_mode(mode->clock, min_bpp << 4) > port->full_pbn) {
>  		*status = MODE_CLOCK_HIGH;
>  		return 0;
>  	}
>  
> +	num_joined_pipes = intel_dp_num_joined_pipes(intel_dp, connector,
> +						     mode->hdisplay, target_clock);
> +
>  	if (intel_dp_has_dsc(connector) && drm_dp_sink_supports_fec(connector->dp.fec_capability)) {
>  		/*
>  		 * TBD pass the connector BPC,
> @@ -1513,6 +1512,19 @@ mst_connector_mode_valid_ctx(struct drm_connector *_connector,
>  	}
>  
>  	*status = intel_mode_valid_max_plane_size(display, mode, num_joined_pipes);
> +
> +	if (*status != MODE_OK)
> +		return 0;
> +
> +	max_dotclk *= num_joined_pipes;
> +
> +	if (mode->clock > max_dotclk) {
> +		*status = MODE_CLOCK_HIGH;
> +		return 0;
> +	}
> +
> +	*status = MODE_OK;

*status is guaranteed to be MODE_OK at this point, so the above could be
dropped (along with the return 0; in the mode->clock > max_dotclk case).
In any case:

Reviewed-by: Imre Deak <imre.deak@intel.com>

> +
>  	return 0;
>  }
>  
> -- 
> 2.45.2
>